Personally i'd stick with the variable-speed Honda. As Merk said, they are heavy. If you do get one, make sure it's self propelled. You'll get tired of a manual pusher pretty quickly.
From here on out - unless it's an older Lawnboy or specifically says '2-stroke', 99.9% of the newer 21" or 22" push mowers are, by default, 4-strokes.